In the Advanced Proteomics Core, we will apply unbiased proteomics approaches to characterize protein- protein interactions (PPIs) and post-translational modifications (PTMs) for transcription factor complexes that play important roles in early heart development. These studies will describe the interconnected networks of transcription factors, chromatin remodeling complexes, and as-yet-undefined cellular factors that function to regulate gene expression during cardiac development. The Proteomics Core will enable research projects to analyze biochemical complexes that underlie cardiac development. Through tagging of these factors, cellular expression, and affinity purification, these complexes will be elucidated by mass spectrometry (AP-MS), and data will be analyzed using newly developed algorithms to determine high confidence protein interactions. Using specific enrichment and mass spectrometry-based approaches, the Proteomics Core will identify post- translational modifications of purified complex components. Chemical enrichment strategies to purify phosphorylated species and antibody-based strategies to purify acetylated or ubiquitylated species will collectively identify modification events that may affect the formation or function of protein complexes underlying cardiac gene expression.